<p>CHARLOTTE, N.C.— U.S. Sen. Rand Paul is endorsing obstetrician Greg Brannon on the eve of the U.S. Senate primary election in North Carolina.</p><p>At a rally in Charlotte, the Kentucky senator said Brannon was the best candidate in Tuesday's crowded GOP field.</p><p>Paul urged the 250 people in the crowd to send another true conservative to the Senate.</p><p>He called Brannon a dragon slayer, someone who would shake up the status quo in Washington.</p><p>Earlier in the day, Mitt Romney, the 2012 Republican presidential nominee, announced his support for state House speaker Thom Tillis in the primary.</p><p>Romney says in an email message that Tillis is a conservative who solved problems while in Raleigh and he thinks Tillis will do the same in Washington.</p><p>Eight Republicans are seeking the party's nomination.</p>